The present invention relates to a method of packing pulverized material such as coffee in a container made of foil or film material, for instance plastic laminate.
It is known to pack pulverized material such as coffee in containers made of film material, and the pulverized material then occupies about two thirds of the volume available. The reason why the container is not filled completely is that the wall of the container becomes electrostatically charged and grains of the pulverized material can adhere to the film at the place where it is sealed. It is therefore necessary to have a certain distance between the pulverized material and the sealing point. It is also known to pack pulverized material in containers of the nature of a film under compression. At the compression, however, the walls are subjected to severe mechanical stresses, and it is therefore necessary to use comparatively thick film material, which makes the wrapping more expensive. Finally, it is also known to pack pulverized material in containers made of film under vacuumizing. However, it is a certain drawback to have an outer air pressure on the wrapping, as the oxygen in the air can penetrate into the wrapping in micro-cracks and pores which are formed to a certain extent. These problems are accentuated at hard vacuumizing, particularly at the packing of products which have hard, sharp grains, such as ground coffee.